Heating pad



March 25, 1952 Filed April 2, 1947 A. o. SAMUELS 2,590,212

HEATING PAD 5 Sheets-Sheet l INVENTOR.

BY WM M ATTORNEYS March 25, 1952 A. o. SAMUELS HEATING PAD 3 Sheets-Sheet 2 Filed April '2, 1947 m m m m A66 0. Samuel? BY W M K/QM ATTORNEYJ Patented Mar. 25, 1952 HEATING PAD Abe O. Samuels, Bridgeport, Conn., assignor to Casco Products Corporation, Bridgeport, Conn., a corporation of Connecticut Application April 2, 1947, Serial No. 738,839

3 Claims.

This invention relates to electric heating pads.

An object of the invention is to provide a flexible therapeutic electric heating pad which may be conveniently secured and held in place on various areas of the body of a user, and which may be readily cleaned and sterilized when soiled.

Another object of the invention is to provide a pad as above used which, in addition to its capacity for applying a dry heat, is so organized that moist or wet heat may be advantageously applied without leaking or spilling of the fluid, or without requiring frequent renewal of the fluid.

A. further object of the invention is to provide a heating pad having all of the above characteristics, together with high thermal efliciency and choice of heats whereby both wet and dry treatments may be administered with maximum effectiveness and benefit.

Still another object of the invention is to provide a heating pad according to the foregoing, whichis entirely safe in use.

A still further object of the invention is to provide a heating pad applicable to various surfaces of the body for prolonged application of heat, and which enables the user to have considerable freedom of movement and to move about within apredetermined area, insofar as the pad is concerned. A feature of the inventionis the provision of a flexible, lightweight, completely wet-proofheating pad. of highthermal efficiency, which also has high mechanicalstrength and resistance to undesirable deformation or distortion.

A further object of the invention is to provide a heating pad as above, which is economical to fabricate.

These and. other objects are accomplished, according to the invention, by an organization including a completely wetproof, flexible heating pad and fabric slip cover, the latter having a pocket arranged to receive the pad, and having substantially coextensive with said pocket and superposed thereon, a second. pocket or recess into which a moisture reservoir in the form of a moistened sheet may be inserted. Tie strings are provided for use with this assemblage, so arranged as to enable the assemblage to be conveniently fastened over the'desired area of the user's body and securely held in place.

The fabric slip cover and tie string are readily separable from the heating pad unit, and therefore may be repeatedly easily washed and laundered, and otherwise sterilized, and since the pad unit itself is completely wetproof and has readily accessible-exposed surfaces, it also may be washed and sterilized. As a consequence, theheating pad assemblage as provided herein is extremely sanitary in all respects.

The moisture reservoir sheet has spongelike characteristics and is so constructed and related to the slip cover and heating pad unit that no leaking or dripping of fluid occurs during use of the pad, and that sufficient moisture is retained for effective treatment over a period of as much as twelve hours, and thus is of considerable advantage in reducing the attention required of trained attendants, for example.

In one embodiment of the invention an applicator sheet is provided, by which salves, ointments and the like may be applied, the said sheet being readily detachable from the slip cover body and replaceable by a fresh sheet, and being so arranged as :to form the means for holding in place the moisture reservoir sheet.

In another embodiment of the invention wherein the pad unit is narrow and elongate in configuration, the thermostatic control means, which have appreciable bulk, are located adjacent the extremities of the pad so as to interfere to the least extent and provide for the maximum possible comfort when the pad is in use, and condensers associated with the said means are included in the housings therefor, eliminating extra hulk.

By virtue of a unique and novel electrical pad construction involving rubberized fabric foundation and envelope sheets, a highly efficient heat transmission is effected from the coils to the, out side of the pad, increasing thermal efiiciency and reducing the maximum internal pad temperatures which are required, while at the same time high mechanical strength and resistance to undesired distortion is retained.

The method of securing the pad assemblage to the body of a user by positive-holding tie strings enables a maximum freedom of movement to be had, so that the user need not be immobilized on account of the pad.

Other features and advantages will hereinafter appear.

In the accompanying drawings:

Figure 1 is a perspective view showing the improved heating pad and slip cover assemblage as provided by the invention, the heating pad being not quite completely inserted in the slip cover.

Fig. 2 is a top plan view of the heating coils of the pad secured to the rubberized textile fabric base or foundation.

Fig. 3 is a plan view of the heating coil and 5-5 of Fig. 3.

Fig. 6 is a transverse section taken on the line 6-6 of Fig. 4.

Fig. 7 is a transverse section taken on the line 11 of Fig. 1.

Fig. 8 is a perspective view of a slip cover made according to a modification of the invention.

Fig. 9 is a perspective view of a larger size heating pad, illustrating also another modification of the invention.

Fig. 10 is a plan view of one of the thermostatic controls, with cover removed, of the pad of Figs. 1 through 7, and

Fig. 11 is a schematic wiring diagram of the heating pad.

'As shown the improved heating pad of the present invention comrises a heating element It formed of the usual spirally wrapped heating element wire H which is disposed in flat convolutions and sewed to a flexible base or foundation sheet l2.

The foundation sheet [2 is of fabric, and may be formed of rubberized fabric which, while being thoroughly impregnated with the rubberizing compound, is of the type formed by rubberizing one side thereof. If the foundation sheet I! is of rubberized fabric, the convolutions of heating element wire I! are preferably sewed to the side of the foundation sheet I2 which has not been rubberized. However, although this side of the sheet has not been rubberized, actually the rubberizing compound exists throughout the sheet and therefore comes in intimate contact with the heating element wire I As shown in Figs. 2 and 11, for the purpose of controlling the operating temperature of the heating element and also to provide a safety factor, thermostats l3 and Mia are included in series with the heating element [0 and are secured by stitches l4 over the opposite ends of the heating coil assemblage. The thermostats l3 and Ba are connected together in series by a wire 15, one thermostat being connected by a second wire IE to one conductor of a rubbercovered supply cord I! the'other conductor of which is connected with an end of the heating element l0.

According to the invention a relatively thick sheet l8 of heat-insulating material is placed over the convolutions of the heating element It and secured along its marginal portions to the marginal portions of the foundation sheet I2 by stitches I9. The sheet I8 of heat insulation, together with the rubberized foundation sheet 12 thus form a flat bag or envelope which completely encloses theheating element In and prevents rumpling of the sheet If! and preferably the rubber-covered electric cord H is brought out through one corner of the bag as shown in Fig. 3,

The assemblage of Fig. 3 is enclosed-in an outer bag or envelope 2!), shown in Fig. 4, which latter is also formed of rubberized textile fabric preferably with the rubberized side out. The marginal portions of the outer envelope 26 may be sealed in any suitable manner as by applying an adhesive compound 2! thereto, and vulcaniz ing the portions together. Duringfsuch operis also vulcanized to the rubber-covered electric 4 cord ll, thereby producing a completely watertight and air-tight, sealed unit.

Referring to Fig. 6, it will be seen that the heating element wires !l are directly in contact with the rubberized foundation sheet i2 and heat the latter to a high temperature, not only by conduction but also by radiation. Also, the

rubberized foundation sheet [2 is adapted to engage the rubberized side 23 of the outer envelope and heat the latter both by conduction and radiation. As a consequence, since the rubberized fabrics are relatively good conductors of heat as compared with untreated textile fabrics which have numerous interstices filled with air, heat from the heating element it! will be eficiently conducted to the exterior surface of the side 23 of the outer envelope, and will heat this side to a relatively high temperature. Due to the efficiency of the heat transmission to the exterior surface of the side 23, the heating element 10 may be maintained at a relatively low tempera ture and still produce a predetermined effective high temperature in the side 23 of the outer envelope.

Considering the opposite side 24 of the outer envelope, it will be observed that there is interposed between this latter side and the heating element It the relatively thick sheet of heat insulation l8. This sheet may be formed of any suitable material having cotton and woolen fibres in varying proportions, and preferably-has 1 large, trapped air spaces which act as'heat 'in-' sulators. As a consequence, the temperature to which the side 24 of the'outer envelope will be heated is considerably lower than the temperature to'which the side 23 is heated. This latter side is thus termed the high side of the heating pad, and the side 24 the low side.

In accordance with the invention, for the purpose of enabling the pad structure above to be used in conveniently applying a hot wet compass to various diiferent affected parts of" the body to be treated, thus to employ the principle of fomentation, a sanitary washable fabric slip cover 25 is provided, having a pocket 26 open at opposite ends into which the heating pad. may

be longitudinally inserted, and having a second pocket 21 open along a longitudinal edge of the.

slip cover for receiving a fomentation or moisture-carrying sheet 28.

The heating pad may be inserted in the slipcover 25 so that either its ,high or its low side is adjacent the fomentation pad 28, and thus either a high or low heat may be applied to the within the slip cover.

As shown in Fig. 1 the heating pad is not quite j completely inserted in the slip cover. When it is fully inserted by shifting it to the right into 7 the slip cover, the ends of the pad and cover will be closely adjacent each other and the supply cord or lead wires i7 will project from the end of the slip cover. The ends of the slip cover 25] are folded to form V-shaped extensions BB, and

tie-strings 3| are secured to the extensions to "project from the pointed ends thereof. Jljreferably the tie-strings 3! and extensions 30' are) secured togetherby rows of stitches 32 which provide a secure anchorage for the strings. 'By' j thisorganization the heating pad of the present invention and fomentation pad 28 may be quickly" and conveniently applied to various parts of the body. For example, the slip cover 25 having the said pads may be secured over the forehead, and tied behind the head by the strings 3i, and either the fomentation pad 28 or the heating pad may be placed nearest the skin. Also, the slip cover maybe readily tied about an arm or leg or other part of the body, wherever wet or dry heat is desired.

It will be seen that the heating pad described above is of extremely simple construction. Through actual test it has been found that the use of a rubberized fabric foundation sheet, together with a rubberized outer envelope in intimate heat-conducting relation with the foundation, produces a pad having a high thermal efficiency thereby enabling the internal temperatures of the pad to be lowered, while still producing a given external temperature. The heating of the element l0 is-not so great as to adversely affect the strength or water-proof properties of the rubberized fabrics used, and it has been found that the resistance to water of the said fabrics increases rather than decreases after the application of heat, and also upon aging.

The amount of rubber used in the entire pad is extremely small, and since rubber is an expensive material as compared with textile fabrics and the like, the cost of material entering into the pad is kept at a low figure. Also, the pad is of extremely light Weight, which is of considerable advantage in many instances.

By the rubberized fabric construction as described above, a pad is produced which is extremely flexible, and yet has a high mechanical strength and is resistant to severe usage under adverse conditions. The pad is not easily deformed nor distorted, and therefore damage or malfunctioning of the heating element is avoided.

It will be noted that the base or foundation sheet l2 also functions as a distributor of heat from the heating element Ill. The sheet I2 receives the heat from the element ill by conduction through direct contact therewith, and also by direct radiation therefrom. In consequence of this, the foundation sheet :2 becomes substantially uniformly heated throughout its area and this heat is then transmitted to the rubberized wall 23 of the outer envelope so as to uniformly heat the said wall.

By virtue of the fact that the rubberized side of the foundation sheet 12 is the side which is in contact with the Wall 23 of the outer envelope, a high transmission of heat is obtained which is better than if the rubberized side of the foundation sheet were to be oppositely located, in contact with the heating wires ll.

Referring to Fig. 6, it will be seen that the foundation sheet I2 also acts as a pad between the heating element wires H and the wall 23 of the outer envelope, and tends to prevent the wires from being easily felt or distinguished from one another through the envelope.

A slip cover 33 illustrating a modification of the invention is shown on Fig. 8. The slip cover 33 comprises an elongate flat tubular body as having squared ends and being preferably open at both ends, whereby the heating pad unit may be easily and quickly fully inserted.

Along the central portion of one side of the body 34 a fabric tape 35 is sewed, the ends of the tape being extended beyond the slip cover body and functioning as the tie strings. By this construction there is obviated the possibility that strong opposed pulls on the ends of the tape 6 will tend to separate it from the body 34 of the slip cover.

A pocket for receiving the fomentation pad 28 is formed by sewing to the opposite side 3.! of the tubular body 34 three edges of a fabric sheet or panel 38 the fourth edge 39 of which is free of the side 31 so that a pocket is thereby formed. Preferably, as shown, the longitudinal edge 39 of the sheet 38 is spaced inward a small distance from the adjacent longitudinal edge of the body 34, thereby providing for more convenient insertion of the fomentation pad 28 since it is possible to more easily initially separate the said spaced longitudinal edges.

A heating pad 45 illustrating another modification of the invention is shown in Fig. 9. This pad comprises a slip cover of rectangular and almost square configuration, in the form of a flat bag having sides 4| and 42 joined together along three edges 43, 44 and 45, leaving an open mouth 45 through which the flexible heating pad unit 41 is inserted. Rows of stitches 48 are provided, extending parallel with and spaced from the edges 43 and 45 to form fiat marginal portions along said edges, and in one marginal portion button holes 49 are provided through which tie strings 50 may be passed.

At the mouth 46 of the slip cover the sides 4| and 42 thereof are provided with cooperable snap fasteners 5| by which the pad unit =3? be retained in the cover.

For the purpose of holding a fomentation pad 52 to the side 42 of the slip cover, and to enable salves and other medication to be applied in a sanitary and convenient manner, an applicator sheet 53 which is preferably of cor ton flannel is provided, said sheet having snap fasteners 5d cooperable with mating fasteners secured to the fiat marginal portions of the slip cover. The applicator sheet 53 and side 42 of the slip cover form a pocket into which the fomentation pad 52 may be readily inserted, and from which it can be easily removed.

By use of the snap fasteners 54 the applicator sheet 5-3 may be easily replaced, so that soiled applicator sheets may be conveniently cleaned as by laundering, and maintained in a sanitary condition.

The heating pad 40 may be easily applied and held to many different afflicted parts of the body by virtue of its complete flexibility and by the provision of the tie springs 53, and may be used to produce either dry or Wet heat, as desired Where a slim member such as a forearm is Wrapped with the pad 49, the edges of the pad may be overlapped and yet permit the pad to be tied in place by the strings 50 since the latter pass through only one of the fiat marginal portions of the slip cover. Due to the removability of the applicator sheet 53 from the slip cover, and of the pad unit 41 from the slip cover, complete cleaning and sterilizing of the entire heating pad is easily accomplished, in-- cluding laundering of the applicator sheet and slip cover.

In accordance with the invention a novel, simple and compact means is provided whereby the tendency of the thermostats I3 and when operating, to interfere with radio reception is minimized. Referring to Fig. 10, the thermostat I3 is provided with a small cylindrical condenser 55a having one end 56 connected with the thermostat terminal 5?, and having the other end 58 connected with a condenser terminal 59 on the thermostat housing 6! As seen in Fig. 11 the condenser terminal of the thermostat I3 is connected by awire Bl to the terminal 51 of thethermostat I 3a whereby the condenser 55a is made to bridge the series-connected thermostats; thus surges due to arcing or sparking which occurs during operation of the thermostats are by-passed through the condenser and prevented from passing out into the supply line. The condenser 55a is small enough to be completely housed in the housing 60 of the thermostat I3, and the circuit and organization is such that no additional space whatsoever in the heating pad unit is required. This is of considerable importance where a heating pad is intended for use in the manner of a wrapping around a part of a users body.

Referring to Fig. 2 the thermostats l3 and I311 are located adjacent opposite ends of the heating pad unit Where I have found their bulk to be least objectionable, thereby providing for a maximum of comfort on the part of a user.

Variations and modifications may be made within the scope of this invention and portions of the improvements may be used without others.

I claim:

1. The combination of an elongate heating pad of generally rectangular configuration, having lead wires extending from one end thereof; a rectangular fomentation pad; and a rectangular slip cover having separate pockets respectively carrying said heating pad, and fomentation pad in superposed relationship, said pads being substantially co-extensive with each other, one of said pockets having a mouth extending along a longitudinal edge of the slip cover and the other pocket having a mouth located at one end of the slip 'coverfand said lead wires projecting from an end of the slip cover; and means secured to the ends of the slip cover for securing the same to the body of a user.

2. A therapeutic device comprising the combination of an electric heating pad; a fomentation pad; a slip cover for use with said pads to secure the same to the body of a wearer, said slip cover having a pair of pockets superposed on and substantially coextensive with each other, carrying respectively the heating pad and fomenbination of an electric heating pad; a fomentation pad; a rectangular slip cover for use with said pads to secure the same to the body of a wearer, said slip cover having a pair of pockets superposed on and substantially co-extensive with each other, carrying respectively the heat ing and fomentation pads, said fomentation pad pocket having a mouth extending along a longitudinal edge of the slip cover and the other pocket having a mouth located at one end of the slip cover, said mouths admitting said pads during assembly of the device; and means located at the ends of the slip cover for securing the same to the body of the user.

ABE O. SAMUELS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,478,497 Welch Dec. 25, 1923 1,486,470 Welch Mar. 11, 1924 1,715,486 Wolfe et a1. June 4, 1929 1,723,373 Roberts Aug. 6, 1929 1,736,590 Graham et al. Nov. 19, 1929 1,813,902 Bovie July 14, 1931 1,835,034 Formaneck Dec. 8, 1931 1,975,329 MacSweeney Oct. 2,1934 2,052,644 Murphy Sept. 1, 1936 2,185,692 McCleary Jan. 2, 1940 2,198,989 Cooley Apr. 20, 1940 2,339,409 Joy et al Jan. 18, 1944 FOREIGN PATENTS Number Country Date 4,581 Great Britain Feb. 24, 1906 373,748 Germany Apr. 16, 1923 

